1. Field of Invention
The present invention is related to a liquid crystal display (LCD) device and, more particularly to a liquid crystal display device used in a wide viewing angle.
2. Related Art
In the liquid crystal display (LCD) device, the light transmission rate is controlled due to the different polarization effects or refraction effects induced by different alignments of the liquid crystal molecules, such that the LCD device can generate the desired image.
In general, the conventional twisted nematic (TN) LCD device has the disadvantage of narrow viewing angles because of the structure and optical features of the liquid crystal molecules. To resolve this issue, some different types of LCD devices with wide viewing angle, e.g. a multi-domain vertical alignment (MVA) LCD device and a patterned vertical alignment (PVA) LCD device, have been developed.
To increase the viewing angle of the LCD device, a pixel is divided into multiple domains with the MVA technology; hence the liquid crystal molecules in different domains may topple down in different directions.
FIG. 1 shows a conventional MVA LCD device 1 that includes two substrates 11 and 12, and a liquid crystal layer 13 disposed between the substrates 11 and 12. The substrate 11 is a driving substrate, on which a pixel electrode 111, a row conductor (not shown), a column conductor (not shown), and a thin film transistor (TFT) (not shown) are formed. The substrate 12 is a counter substrate, on which a counter electrode 121 and a color filter (not shown) are formed.
The alignment films 112 and 122 that are individually accommodated in the substrates 11 and 12 are used to vertically align the liquid crystal molecules of the liquid crystal layer 13. The substrates 11 and 12 further include convex structures 113 and 123, respectively, which are located between the pixel electrode 111 and the counter electrode 121. When a potential difference is applied to the substrates 11 and 12, the liquid crystal layer 13 is placed in the electric field generated by the potential difference, so that the liquid crystal molecules of the liquid crystal layer 13, which is affected by the electric field and the convex structures 113 and 123, will topple down in different directions.
However, in the perspective of the light emitting surface or the light incident surface of the LCD device 1, the convex structures 113 and 123 may affect the aperture ratio for they are located within the pixel electrode of the pixel, and since the liquid crystal molecules between the convex structures 113 and 123 are not affected by the electric field and do not topple down, the singular point is generated in each pixel and this will cause flaws in the displayed image.
Therefore, a LCD device with wide viewing angle that contains no singular point is highly desired to solve the above issues.